Many arc discharge lamps, including fluorescent lamps, require mercury to function properly. In the past, mercury has been dispensed into fluorescent lamps during processing of the lamps by simply injecting, in one manner or another, a quantity of liquid mercury. Occasionally the mercury has been included in the lamp in the form of an amalgam. Since mercury can be a hazardous substance it would be an advance in the art to develop a system to dispense into a lamp only the necessary amount of mercury. One such system includes a container having the requisite supply of mercury therein, which container is mounted within the fluorescent lamp during processing and subsequently heated to melt a plug within the container, thereby releasing the mercury. Although this system is workable, it has increased cost due to the necessary forming of the escape hole, the solder placement and the cost of the solder. Additionally, the entire cost of the manufacturing is high compared to the present invention.